Project Summary Detection and management of acute HIV infection (AHI) is a clinical and public health emergency, and HIV infections diagnosed among young adults are usually recent. Young adults with recent HIV acquisition frequently seek care for symptoms, and could potentially be diagnosed through the health care system. Although over 50% of persons living with HIV infection in Kenya are unaware of their status, facility-based HIV testing is underutilized and available tests cannot diagnose AHI. Early recognition of HIV infection provides considerable individual and public health benefits, including reduction in risk behavior, notification of partners in need of HIV testing, access to counseling and treatment, and viral load suppression, if achieved. In this R01 application, we propose a multidisciplinary research project that builds on pilot work carried out in coastal Kenya to detect AHI among young adults seeking care for symptoms compatible with acute retroviral syndrome. Our highly productive research team, including collaborators from the University of Washington, University of Oxford, and Kenya Medical Research Institute, has expertise in the fields of clinical care (Dr. Graham), HIV prevention (Dr. Sanders), partner counseling and notification services (Dr. Farquhar), risk behavior and network evaluations (Dr. Goodreau), and costing of interventions (Dr. Babigumira). Our specific aims are to: (1) identify and test 1,500 adults identified by our AHI screening algorithm for acute and prevalent (i.e., seropositive) HIV, linking all newly diagnosed HIV-infected patients to care and offering immediate treatment; (2) offer assisted partner notification services (aPS) to all cases detected, screening partners for acute and prevalent HIV infection and identifying local sexual networks; and (3) model the potential impact of these two interventions on the Kenyan HIV epidemic, estimating incremental costs per HIV infection averted, death averted, and disability-adjusted life-year averted using data on outcomes from our innovative program. We will use a modified stepped wedge design to evaluate the yield of this screening intervention at 2 public and 4 private health facilities in coastal Kenya, before and after intervention delivery. Our innovative intervention will use standard HIV rapid tests to diagnose prevalent HIV infection and point-of-care HIV-1 RNA testing to diagnose AHI among young adults presenting for care; use aPS to identify linked acute and prevalent infections; and follow all newly diagnosed patients and their partners for 12 months to ascertain clinical outcomes including linkage to care, ART initiation and virologic suppression in HIV-infected patients, and PrEP uptake in uninfected individuals in discordant partnerships. Building on our pilot work on AHI screening (Clinicaltrials.gov, NCT01876199) and our ground-breaking work on aPS in Kenya (Clinicaltrials.gov, NCT01616420), as well as our expertise in modeling and cost-effectiveness analysis, we will provide foundational data on the potential of this novel, combination HIV prevention intervention to significantly reduce ongoing HIV transmission in Kenya and other high-prevalence African settings.